Some symptoms are time-critical, meaning the treatment only works if it happens quickly. For those, a walk-in queue, a clinic appointment tomorrow, or a phone call to your doctor is the wrong choice — go to the emergency department, or call 911. The list is shorter than people fear and more specific than general advice suggests: chest pain, stroke signs, severe breathing difficulty, throat or facial swelling, uncontrolled bleeding, a head injury with vomiting or confusion, sudden severe abdominal pain, a sudden worst-ever headache, sudden vision loss, a fever in a baby under three months, new confusion or seizure, a visibly deformed bone, and suicidal thoughts with a plan. If you are reading this while experiencing any of them, stop reading and call 911.
This article is about recognising emergencies. It is not a substitute for assessment. If you are unsure at any point, call 911 or Health811 at 811 — being wrong about an emergency costs far more than being wrong about a clinic visit.
Call 911 immediately
Do not drive yourself. Do not wait to see if it passes.
Heart
- Chest pain, pressure, tightness or squeezing
- Pain spreading to the jaw, neck, shoulder, arm or back
- Chest discomfort with sweating, nausea, breathlessness or lightheadedness
- A sense of impending doom alongside any of the above
Women, older adults and people with diabetes often have atypical symptoms — nausea, unusual fatigue, shortness of breath or back pain without classic chest pain. Do not dismiss them for not looking like the films.
Brain
Act FAST:
- Face drooping on one side
- Arm weakness or numbness on one side
- Speech slurred, strange, or unable to speak
- Time — call 911 now, and note when symptoms started
Also 911 for: sudden severe worst-ever headache, sudden confusion, sudden vision loss or double vision, sudden loss of balance or coordination, or a seizure.
Stroke treatment is governed by a clock. The window for the most effective treatments is measured in hours from the moment symptoms began, which is why the start time matters and why a walk-in visit wastes the only thing that counts.
Breathing
- Severe difficulty breathing, or breathing that is getting rapidly worse
- Unable to speak a full sentence
- Blue or grey lips, face or fingertips
- Gasping, or noisy breathing with visible effort
- An asthma attack not responding to a reliever inhaler
- Choking
Allergy
- Swelling of the lips, tongue, throat or face
- Difficulty swallowing, or a tight throat
- Widespread hives with breathlessness, vomiting or faintness
- Any known severe allergy after exposure
Use an epinephrine auto-injector if prescribed, then call 911 regardless of improvement — symptoms can return.
Severe infection
- High fever with confusion or extreme drowsiness
- Very low blood pressure, or feeling faint on standing
- Mottled, grey or blotchy skin
- A rash that does not fade when pressed
- A stiff neck with fever, headache and sensitivity to light
- Rapid breathing with fever and a feeling of impending collapse
Other 911 situations
- Bleeding that will not stop with firm pressure
- A major injury, fall from height, or high-speed collision
- Unconsciousness, or difficulty rousing someone
- Suspected overdose or poisoning
- A burn that is large, deep, or involves the face, hands, genitals or an airway
- Electrical injury
- A seizure lasting more than five minutes, or repeated seizures
Go to the emergency department — do not use a walk-in
Driving is reasonable for these if you are not the patient and the patient is stable.
Head and neurological
- A head injury followed by vomiting, confusion, drowsiness, worsening headache or any loss of consciousness
- A head injury in someone on blood thinners — regardless of how minor it looks
- New weakness, numbness or tingling on one side
- A severe headache that is different from your usual ones
Abdomen
- Sudden severe abdominal pain
- A hard, rigid or exquisitely tender abdomen
- Abdominal pain with persistent vomiting and no bowel movement
- Pain in the lower right abdomen with fever
- Vomiting blood, or material that looks like coffee grounds
- Black, tarry stools, or significant rectal bleeding
- Testicular pain of sudden onset — time-critical, go now
Bones and injuries
- A bone visibly deformed, or protruding through the skin
- An injured limb that is cold, pale, numb or pulseless
- Inability to bear any weight after an injury
- A dislocated joint
- A deep wound to a hand, foot, joint or the face
- Any animal or human bite to the hand, or a deep bite anywhere
- A wound with something still embedded in it
Eyes
- Sudden vision loss or a curtain across your vision
- Chemical splash to the eye — irrigate with water for 15 minutes on the way
- A penetrating eye injury
- Severe eye pain with redness and vision change
- Flashes and floaters of sudden onset with a shadow in your vision
Pregnancy
- Any bleeding in pregnancy
- Severe abdominal pain in pregnancy
- Severe headache, vision changes or swelling in later pregnancy
- Reduced or absent fetal movement
- Fluid leaking before term
Children
- Any fever in a baby under three months — no exceptions
- A child who is floppy, inconsolable, unusually drowsy or hard to wake
- A child who is not drinking and has no wet nappies
- Rapid or laboured breathing, or a chest that pulls in with each breath
- A rash that does not fade when pressed
- A child with a seizure
- Persistent vomiting in an infant, or vomiting that is green
- A limp child after a head injury
- A parent’s strong instinct that something is seriously wrong — trust it
Mental health
- Suicidal thoughts with intent, a plan or the means
- Thoughts of harming someone else
- Hearing voices or losing touch with reality for the first time
- Being unable to keep yourself safe
You will be taken seriously. You do not need to be in crisis to deserve care.
Time-critical, but a walk-in or same-day clinic visit is appropriate
Not emergencies — but they get worse by the hour, so today matters.
| Problem | Why today |
|---|---|
| A painful band-like rash on one side of the body | Possible shingles; antiviral treatment works best started early |
| A cut that may need stitches | Closure becomes harder and infection risk rises with time |
| A tick attached to the skin | Earlier removal lowers risk |
| A urinary infection with any back pain or fever | Can progress to a kidney infection |
| Spreading redness around a wound | Early cellulitis treated orally beats late cellulitis treated by IV |
| An eye that is red, painful and light-sensitive | Needs assessment today |
| Emergency contraception | Effectiveness falls with every hour |
| A wound in someone with diabetes or poor circulation | Low threshold, early assessment |
| A fever that persists beyond a few days | Needs examination |
| Vomiting with inability to keep fluids down for over 24 hours | Dehydration risk |
When you genuinely cannot tell
Call 811. Health811 connects you with a registered nurse, free, at any hour, and they will tell you where to go. It exists exactly for this uncertainty.
Three principles for the grey zone:
- Sudden, severe, or different from anything before — treat as an emergency.
- Getting worse quickly matters more than how bad it is right now.
- If you are frightened, that is information. Patients and parents are often right.
Nobody will criticise you for going to the emergency department and being sent home. That is a correct outcome. The failure mode everyone in medicine worries about is the person who stayed home.
FAQ
Should I drive myself if I have chest pain?
No. Call 911. Paramedics can begin treatment on the way, and they can resuscitate you — nobody can do that while you are driving.
Will I be judged for coming in and it turning out to be nothing?
No. Ruling out an emergency is the job. Emergency staff would far rather see ten people whose symptoms turned out to be benign than miss one.
What if the walk-in is closer than the hospital?
For anything on these lists, go to the hospital or call 911 anyway. A walk-in clinic will simply send you on, and you will have lost the time.
What if I go to a walk-in and they send me to emergency?
Go straight there, and bring their note — it moves you through triage faster.
Does a long ER wait mean I should go elsewhere?
No. Triage is by severity, so genuinely urgent problems are not waiting four hours. Never let a posted wait time delay an emergency.
What if it is the middle of the night?
Emergency departments do not close, and 811 answers at every hour. Neither of them cares what time it is.
My symptoms resolved on the way. Should I still go?
For stroke symptoms, chest pain, an allergic reaction or a seizure — yes. Symptoms that pass can be warnings of something imminent.
What about an older relative who seems “just confused”?
New confusion in an older adult is a red flag, not a normal part of ageing. It can mean infection, stroke, medication problems or dehydration. Get them assessed today.
For everything that is not on these lists
Milton Health Centre’s walk-in clinic can treat the large majority of same-day problems — infections, minor injuries, rashes, prescriptions — and our family practice looks after everything ongoing. See hours and services at Milton Health Centre.
For anything on this page, go to the emergency department or call 911. Do not come to us first.
Related reading
- Walk-In Clinic, Urgent Care or Emergency Room? A Milton Patient’s Decision Guide
- What a Walk-In Clinic Can Treat the Same Day
- Why Emergency Room Waits Are So Long — and What It Means for You
- How to Register as a New Patient at Milton Health Centre
This article provides general health information for Ontario residents and is not medical advice, and it cannot cover every emergency. It is not a substitute for assessment of your own symptoms. If you believe you or someone else is having a medical emergency, call 911 or go to the nearest emergency department immediately. For health advice at any hour, call Health811 at 811. In a mental health crisis, call 911 or 988, Canada’s suicide crisis helpline.